Projectile timing



H. G. BUSlGNIES E-r AL, 2,465,351

PROJECTILE TIMING Filed March 26, 1943 ATTU)? EV Patented Mar. 29, 19492,465,351 rRoJEc'rrLE TIMING Henri G. Busignies, Forest Hills, and LouisA. De Rosa, Staten Island, N. Y., assignors to Federal Telephone andRadio Corporation, Newark, N. J a corporation of Delaware ApplicationMarch 26, 1943, Serial No. 480,632

This invention relates to munitions and more particularly'to timecontrol of detonatable projectiles such as shells fired by guns.

In the copending application of E. M. Deloraine entitled Electricaldetonation system, Serial No. 88,036, filed April 11, 1941, whichapplication is now abandoned, several forms of electromagneticallycontrolled fuses for detonatable shells are disclosed. The initiation ofthe timing operation for certain of the electrical fuses thereindisclosed is controlled by the firing of the shell through a magneticfield located at the muzzle of the gun. The intensity of the field iscontrolled and the circuit for the fuse is so constructed and arrangedas to provide a surge of voltage which is used to perform a timingoperation with the view to detonating the shell a determinable timeinterval after the firing of the gun.

One of the objects of our invention is to pro-' magneticmeans for theestablishment of a magnetic field the intensity of which is controlledsimilarly as set forth in the aforesaid Deloraine application. Thedetonatable shell is preferably provided with a point detonating-fuse ofthe combination impact and time character together with an electricalcircuit for timing within limits the firing of the fuse. This circuitincludes a shock excitable L.-C. circuit which produces an oscillatorywave when the shell is projected through the magnetic field. The speedof the shell and the intensity of the field determine the amplitude ofthe oscillations established in the L.-C. circuit. Arranged in parallelwith the fuse element of the circuit is an energy storing device such asa condenser, together ,with means for rectifying the oscillations of theL.-C. circuit whereby rectified energy is stored in the condenser. Whenthe voltage of the stored energy reaches a predetermined amount theenergy is discharged through the fuse element, thereby detonating theexplosive charge of the shell. This discharge of the stored energy iscontrolled by a gas-filled tube which is carefully constructed tooperate at substantially a predetermined voltage.

Claims. (Cl. 102-102) For increased accuracy of the timing operation,the rectifier means and the energy discharge tube may be combined as asingle gas-filled tube having two pairs of electrodes, such as disclosedin our co-pending divisional application, Serial No. 550,130, filedAugust 19, 1944, now Patent No. 2,444,427. One pair of the electrodesmay be used to perform the rectifying operation while the second pair ofelectrodes control the discharge of the stored energy. By associatingthe two pairs of electrodes in a single tube, the ionization at thefirst pair of electrodes may be used to periodically prime the gap atthe second pair of electrodes. That is to say, the periodic conductionoccurring at the rectifying operation of the first pair of electrodeswill each time partially ionize the gap between the second pair ofelectrodes so that when the voltage of the stored energy closelyapproximates the predetermined value, the sec-- ond pair of electrodeswill conduct in synchronism with the conduction at the first pair ofelectrodes.- Thus, the detonation will occur a time interval equal tosubstantially a multiple of the wavelength at which the L.-C. circuit istuned. This interval, however, will vary according to the muzzlevelocity of the shell and the intensity of the magnetic field. Byincreasing the magnetic field, the shell will explode soonenand shouldthe muzzle velocity be less than normal the interval will be increasedso as to substantially compensate for the decrease in muzzle velocity.

For a further understanding of the invention, reference may be had tothe following detailed description to be read in connection with theaccompanying drawings, in which:

Fig. 1 is a diagrammatical, longitudinal cross sectional view of themuzzle of a cannon or other shell projecting device provided with meansfor establishing a magnetic field.

Fig. 2 isa side elevational view of a shell provided with anelectromagnetically operated iuse;

Fig. 3 is a schematic wiring diagram of the electromagnetically operatedfuse.

Fig. 4 is a graphical illustration of the timing operation of theelectrically operated fuse; and

Fig. 5 is a view in longitudinal cross section of I a gas-filled tubewhich may be used in the electrlcal timing circuit.

' Referring to Figs. 1, 2, 3 and 4, a gun muzzle I0 is shown providedwith a pair of magnetic coils H and I2 connected by circuit id to asource of energy B and a rheostat I5 by which the energy supplied to thecoils II and I2 is controlled. The coils H and I2 are suitably arrangedin the muzzle l0 so as to provide a magnetic field l8 3 through whichthe shell 2|), such as shown in Fig. 2, must pass when projected by thegun. The shell is provided with an electrom-agnetically operated timingcircuit 22, Fig. 3. This timing circuit comprises a resonant L.-C.circuit which is responsive to the field l8 when the shell is projectedther'ethrough to set up an oscillatory wave 30 (curve a, Fig. 4) It willbe understood,

.- of course, that the coils II and I2 are so arranged as to provide adesirable amount of magnetic fiux where the coil L will cut the samewhen the shell is fired from the gun.

The timing circuit 22 includes a fuse element F and an energy storingdevice such as condenser 24. The oscillations 30 established by theL.-C. circuit are rectified by means such as a gas-filled tube 25 andapplied through a limiting resistor R to the condenser 24. Connected inparallel with the rectifier tube 25 and resistor R on the one hand andthe condenser 24 on the other hand is the fuse element F and an energydischarge tube 26. This timing circuit makes up into a compact unitwhich is enclosed within the shell substantially as indicated in Fig. 2.The

coil L is preferably disposed adjacent the side wall of the shell, butother arrangements may be made so long as the circuit will be shockexcited when the shell is projected through the magnetic field l8.

The operation of the electromagnetically controlled timing circuit maybe better understood by reference to Fig. 4 in which all the curves areapplied to the same time base. Curve a as hereinbefore stated representsthe oscillatory wave 30 established in the L.- C. circuit. Curve brepresents the pulses of rectified energy 3| produced by the rectifiertube 25 in response to the wave 30. Curve c represents the building upof stored energy in the condenser 24 according to the supply of therectified energy 3|. It will be noted that the energy stores up insteps," the stored energy increasing in voltage a small amount for eachof the steps 32. Since the wave ",l a ped and the pulse energy 3|decreases incline, the steps 32 of the stored energy become less andless as the shell continues in its flight.

jAssuming that the level 34 represents a predternii'ned voltage value atwhich the tube 26 will c'onductg it will :be clear that energy of thecondenser 24 will discharge through the fuse elementF a time interval t1after the firing of the shell. By varying-the field intensity 18 bymanipulation of the rheostat' I5, the rapidity of the voltage build-upat the condenser 24 may be controlled. Thus, the'time interval requiredfor the stored energy to build up to the level 34 may be varied at theposition of the gun by controlling the rheostat l5. It will, therefore,be clear that according to our invention, the accuracy of fuse timing isgreatly improved.

In Fig. 5, we have shown an improved gas-filled tube construction 40,such as disclosed in our aforesaid co-pending divisional application,which may be used in the place of the tubes 25 and 2-6 of Fig. 3. Thetube 40 comprises a metal sleeve 4|, such as nickel, the ends of whichare closed by glass beads 42 and 43. Disposed throughthe beads are twopairs of electrodes. The first pair 44, 46 correspond to the electrodesof the tube 25 while the second pair of electrodes 46, 41 correspond tothe electrodes of the tube 26. Disposed between the two pairs ofelectrodes is a partition 48 which may be of any suitable form so longas it provides a limit communication between the spaces containing thetwo pairs of shell having an electromagnetically responsive I 4electrodes. For example, the partition may comprise the i'orm of ascreen or other foraminous member or as shown, may comprise a platehaving one or more openings 5| disposed in the vicinity of the gapsbetween the electrodes 44, 46 and 46, 41. The gas filling the tube maycomprise any suitable'inert gas such as neon, argon, helium, krypton orany desired mixture thereof. 7 The electrodes 44, 45 are so spaced as toprovide rectification of a substantial portion of each positive hall. ofthe oscillating cycles oi the wave 30. Upon conduction, the ionizationof the gas at the gap between electrodes 44, 45 will provide a partialionization through the opening 5| to the gap between electrodes 46, 41.This partial ionization, however, is insuificientto cause conductionbetween the electrodes 46, 41 until the voltage across these electrodesis nearly high enough to initiate the conduction. When thispredetermined voltage value is reached, this partial ionization whichoccurs each time conduction is established between the electrodes 44, 45determines the instant at which the electrodes 46, 41 conducts. Thus, itwill be clear that the conduction of the electrodes 46, 41 occurs aninterval of time after the firing of the gun equal to a multiple of theoscillations of the wave 30. This provides for a more accuratepredictionv of the detonation of the shell according to the ad-J'ustment of the rheostat l5.

It will be recognized by those skilled in the art that the partition 48may be dispensed with where the spacing between the two pairs ofelectrodes is such that the ionization occurring at the electrodes 44,45 will-produce the desired partial ionization at the electrodes 46, 41.For compactness, however, the partition 48 is desirable was to limit theionization of the space at the electrodes 48, 41 upon conduction atelectrodes 44, 45.

While we have shown and described-the principles of our invention inconnection with a specific apparatus, we recognize that various changesand modifications may be made therein without departing from theinvention. For example, rectifying and discharge means other thangas-filled tubes may be used in the timing circuit. It is our aim,therefore, to cover in the appended claims all such changes andmodifications as fall within the scope of the invention.

We claim:

1. A method of timing the detonation of a circuit for timing the fusethereof, comprising establishing a magnetic field through which theshell must travel when projected by the firing'of a gun whereby thecircuit is shock excited to produce an oscillatory wave, rectifying saidwave,

storing the rectified energy, and applying the stored energy in a mannerto effect control of the fuse element for detonation of the shell whenthe stored energy reaches a predetermined voltage.

2. The method defined in claim 1, wherein the strength of the magneticfield is adjusted to control the amplitude of the wave produced in thecircuit thereby determining substantially the time interval between thefiring of the gun and the detonation of theshell projected thereby.

3. An electromagnetically operated timing circuit for the fuse elementof detonatable shells,

' comprising means shock excitable by the passage 'of the shell througha magnetic field to produce an oscillator-y wave, an energy storagedevice, means for rectifying the energy of said wave to charge saidstorage device, and meansto discharge the stored energy of said devicein a manner to control the ignition of said fuse element for detonationof the shell when the stored energy circuit of claim 3, wherein therectifying means comprises a gas-filled tube.

6. The electromagnetically operated timing circuit defined in claim 3,wherein the means for discharging the stored energy includes a gasfilledtube.

7. The electromagnetically operated timing circuit defined in claim 3,wherein the rectifying means and the means for discharging the storedenergy each comprise a gas-filled tube.

8. An electromagnetically operated timing circuit for the fuse elementof detonatable shells, comprising means shock excitable by passage ofthe shell through a magnetic field to produce an oscillatory wave, anenergy storage device, a gasfilled tube having two pairs of electrodes,one pair being connected in circuit as a rectifier for rectifying theenergy of said wave to charge said storage device, the second pair ofelectrodes being connected in circuit as an energy discharge deviceoperable when the stored energy reaches a given voltage to discharge thestored energy through said fuse element.

9. An electromagnetically operated timing circuit for the fuse elementof detonatable shells, comprising means shock excitable by passage ofthe shell through a magnetic field to produce an oscillatory wave, anenergy storage device, a gasfilled tube having two pairs of electrodes,one pair being connected in circuit as a rectifier for rectifying theenergy of said wave to charge said storage device, the second pair ofelectrodes being connected in circuit as an energy discharge deviceoperable when the stored energy reaches a given voltage to discharge thestored energy through said fuse element, and means providing a limitedcommunication between said two pairs of electrodes so that the periodicionization at said one pair of electrodes operates to partially ionizethe gas particles at the gap of the second pair of electrodes, therebyinsuring conduction of the latter electrodes in substantial synchronismwith conduction of the first pair of electrodes when the voltage of thestored energy closely approximates said given voltage.

10. The electromagnetically operated time control fuse defined in claim9, wherein the lastnamed means comprises a partition disposed betweenthe two pair of electrodes, said partition having means permitting thelimited communication between the spaces in which the two pairs ofelectrodes are disposed.

HENRI G. BUSIGNIES. LOUIS A. DE ROSA.

REFERENCES crrEn The following references are of record in the file ofthis patent:

UNITED STATES PATENTS FOREIGN PATENTS Country Number Number Date France1941

